Yes... and be very happy.
Don't update to 8.0... wait for 8.1. There are loads of 'bugs' in the 8.0.0 version, and sw-soft is taking their sweet time to release a fix.
Be glad that you are still on a stable release of Plesk, and stay with it as long as you can. Nothing good comes from the 8.0.0 version, anyway.
As for what you missed, check the autoinstaller log. Also, try updating from SSH if you really really have to. There is a 1.4mb autoinstaller file on the Plesk downloads page that you run from shell, and it will essentially echo out everything as it goes, and allow you to find the exact spot a problem happens.
But again, I highly suggest you stay with 7.5.4